It is often considered desirable to retract a radio antenna into the body of a vehicle such as a passenger automobile. There are numerous reasons, but in the case of such an automobile they include leaving the car lines clean when the radio is not in use and presenting fewer visible clues of the existence of or nature of radio equipment within the vehicle. The use of electrically powered mechanisms, coupled through a flexible rod, or cable element, makes it convenient to extend or retract telescopic antenna elements at will from inside the vehicle. U.S. Pat. No. 4,323,902 to J. L. Hussey et al. is an example of such a powered telescopic antenna.
A need for multiband operation has led to systems in which an additional band, besides e.g., the AM/FM commercial broadcast reception band, capability has been added as shown for example in the U.S. Pat. No. 4,325,069 to J. F. Hills. In this case, a telescopic antenna is modified by adding to the next-to-the-top segment a loading coil module which produces an effective length suitable for transmission and reception in the citizens' band while still providing acceptable reception in the mentioned commercial broadcast band.